While New Orleans is probably the best known city for its cemeteries, New York has some really lovely ones.
A magnet for history buffs and bird watchers, Green-Wood is a Revolutionary War historic site (the Battle of Long Island was fought in 1776 across what is now its grounds), a designated site on the Civil War Discovery Trail and a registered member of the Audubon Cooperative Sanctuary System.
On September 27, 2006, Green-Wood was designated a National Historic Landmark by the United States Department of the Interior, which recognized its national significance in art, architecture, landscaping and history.
[From the Green-Wood website]
In the course of visiting one has to contemplate the value of such spaces in the urban realm. For me, this cemetery provides a different kind of open space. One where quiet contemplation is the norm and not quite such an elusive task as it would be in a more heavily and actively used space, like nearby Prospect Park. I think of the space as a welcome pause for existential mulling, where one can see the leaves change, hike myriad paths, and observe nature (especially birds) without being run over by children or dogs, or hit in the head with a Frisbee.
If, however, you are of the mind that allocating so much land and resources to the dead is not the most efficient use of resources, this article on rethinking how we memorialize the dead may be of interest. These are some pretty compelling ideas and are certainly food for thought in terms of how we integrate memory, religion, and our dear departed into our current landscapes. There was also a recent article in Slate on tiny wooden spirit houses in Alaskan cemeteries, which demonstrates a more personal approach to architecture for the departed.